Soybean whey protein-polysaccharide complex



United tates Patent Ofifi ce 3,069,327 Patented Dec. 18, 1962 a 069 327SOYBEAN WHEY PRbTElIN-POLYSACCHARIDE COMPLEX Arthur C. Eldridge, Morton,and Arlo M. Nash and Allan units of lipoxidase per gram. Since ourlipoxidasecontaining complexes are inexpensive to prepare, the mildbleaching action of lipoxidase may now be extended to other applicationswhere such an action is desired.

K. Smith, Peoria, Ill., assignors to the United States of 5 S fis ;g iig g i i g ii t gg 8; America as represented by the Secretary ofAgriculture P p No Drawing Filed Sept. 19, 1960, seLNo. 57,081 the basisof a nitrogen factor of 6.35 it is apparent that 4 Claims (CL 195 53 ourcomplexes comprise about 3-0 to 80 percent protein. (Granted under Title35, US. Code (1952), sec. 266) A principal object of our invention isthe preparation of a valuable product from soybean whey solution. An- Anonexclusive, irrevocable, royalty-free license in other object is theremoval of substantial amounts of the invention herein described,throughout the world for proteinaceous material from soybean whey beforedisall purposes of the United States Government, with the posal, thusreducing the subsequent BOD thereof. A power to grant s-ublicenses forsuch purposes, is hereby more specific object is the preparation of alipoxidasegranted to the Government of the United States ofAmercontaining product having at least 4 times the lipoxidase ica.activity per milligram of nitrogen as does commercial This inventionrelates to novel and highly useful prodsoybean flour. Other objects willbecome apparent hereucts comprising specific polysaccharide gumcomplexes inafter. of the proteins comprising soybean whey. The instantinvention comprises the discovery that when Soybean whey is the wellknown burdensome liquid a small amount of an aqueous solution of apolysacremaining after the removal of the protein which is isocharidegum such as Irish moss, gum karaya, sodium algielectrically precipitatedfrom an aqueous extract of denate, alginic acid, or agar is added todefatted soybean fatted soybean meal. Soybean whey comprises a mixmealwhey solution, the polysaccharide complexes with ture of dissolvedproteinaceous substances including the proteinaceous material therein,to form a recoverable trypsin inhibitor, hemagglutinin, proteases,amylase, and precipitate which upon lyophilization (freeze drying),lipoxidase, nonprotein nitrogen compounds, and carbocontains the saidlarge values of protein and available hydrates. Although nearlyone-third of the original soylipoxidase. bean meal may be recovered assolids from the soybean Table I shows the assay values for the complexesof whey by evaporation, the whey solids comprise protein this invention.The lipoxidase contents were obtained by only to the extent of 8-12percent, and commercial rethe spectrophotometric method of Theorell etal., Methcovery by evaporation is not practicable despite the fact odsof Biochemical Analysis, vol. 2, p. 113 (1955), pubthat this protein isrich in most of the essential amino lished by Interscience PubL, Inc.,New York City.

TABLE I Amt, Percent Percent Percent (grrs. in in L. U. ling. L. U. lgm.whey lipoxidase Polysaccharide soln. complex N in of protein comcomplexadded/l (dry complex complex co'mplexed of whey basis) plexed Irish mossextractivcs 2. 16 10.10 13. 509 o 2. 17 9. 74 13, 029 Sodium alginate 1.21 11. 98 22, 462 D 2. 02 s. 23 10, 559 6. 50 5. 26 10, 767 2. 4.48 1,724 2. 02 5.34 1.21 9. 70 Locust bean gum.-- 2. 70 8. 14

1 Lipoxidase units.

acids. In present industrial practice there is no attempt to recover thesoybean whey proteins, and vast quantities of soybean whey solution aresimply discarded into sewage disposal systems Where they greatlyincrease the BOD (biological oxygen demand).

Lipoxidase is a water-soluble enzyme known to be present in defattedsoybean meal and in soybean whey (soybean whey contains about 115lipoxidase units/mg. N, or about 77,200 lipoxidase units per liter whenthe extraction ratio is 15:1). Commercially it is conventional to admixabout 0.5 percent of raw soybean meal with unbleached bread flour in thepresence of a trace of an oil comprising unsaturated fatty acids such aslinoleic acid. The lipoxidase of the soybean meal forms labile fattyhydroperoxides thereof which in turn oxidize the carotene that isresponsible for the yellowness of unbleached wheat flour. Althoughhighly purified lipoxidase may be obtained by the method of Guthrie, US.2,216,174, its price per milligram virtually restricts its use tobiochemical investigation. Because of the prior removal ofisoelectrically precipitated non-lipoxidase protein, our novel complexescontain about four times as much lipoxidase per milligram of nitrogenpresent as does commercial soybean meal and flour which contain about3000-4000 The following examples are presented to further teach thepractice of our invention.

Example 1 PREPARATION OF SOYBEAN WHEY 400 g. of hexane-extracteduntoasted oil-free soybean meal was mechanically stirred for a half hourin 4000 ml. water, the pH being adjusted to 7.4-7.6 with NaOH. Thesolids were then separated by centrifuging, resuspended in 2000 ml,water, and recentrifuged, the supernatant then being combined with theprevious supernatant. The pH of the combined supernatant was lowered to4.4-4.6 with HCl and the resulting precipitate was removed bycentrifugation, leaving 4,700 ml. of soybean whey solution having alipoxidase activity of 117 units per mg. of nitrogen (77,200 lipoxidaseunits per liter).

Example 2 PREPARATION OF ALGINATE-SOYBEAN WHEY PROTEIN COMPLEX To 4,700ml. of soybean whey solution obtained as in Example 1 was added 500 ml.of an aqueous solution containing 5.7 g. of sodium alginate. Thesolution was mechanically stirred for 2 hours and then allowed toprecipitate overnight at room temperature. The solids were separated bycentrifugation and then lyophilized to yield 15 g. of dry solidsanalyzing 11.98 percent nitrogen (equivalent to 76.2 percent protein)and representing 63 percent of the total protein originally present inthe soybean whey solution.

Example 3 Example 4 PREPARATION OF ALGINATE-SOYBEAN WHEY PROTEIN COMPLEXTo 4,700 ml. of soybean whey obtained as in Example 1 was added 400 ml.of an aqueous solution containing 9.5 g. of sodium alginate. 23.0 g. oflyophilized complex assaying 8.23 percent nitrogen and representing a 71per cent recovery of the soybean whey proteins was obtained.

Example 5 OF GUM KARAYA SOYBEAN WHEY PROTEIN COMPLEX To 4,700 ml. ofsoybean whey obtained as in Example 1 was added 800 ml. of an equeoussolution containing 30.6 g. of gum karaya. 38.0 of lyophilized complexassaying 5.26 percent nitrogen and representing a 66 percent recovery ofthe whey proteins was obtained.

Example 6 BLEACHING OF UNBLEACHED WHEAT FLOUR WITH SOYBEAN WHEY-ALGINATECOMPLEX A bread dough was prepared by intimately mixing 100 g. ofunbleached wheat flour with a solution containing 62 ml. water, 0.4 g.soybean-alginate complex, 1.0 linoleic acid, and NaOH (to pH 7.0). Aftermixing for five minutes in a dough mixer, the mass was incubated at 37C. for three hours and then freeze dried. The dry material PREPARATIONwas then ground to a flour, and the residual carotene 4 was measuredspectrophotometrically as described in A.O.A.C., 7th ed., p. 206 (1950),published by Association of Oflicial Agricultural Chemists, Washington4, DC.

The results show that the original wheat flour contained 1.85 p.p.m.carotene whereas the test product contained only 0.78 ppm. carotene,thus showing that our soybean-alginate complex significantly reduces theamount of colored component present in unbleached wheat flour.

Having fully disclosed our invention, we claim:

1. The method which comprises mixing lipoxidase-containing soybean wheywith a water solution of a polysaccharide gum and recovering from thereaction mixture a complex of soybean whey proteins and thepolysaccharide gum having lipoxidase activity.

2. The method which comprises mixing lipoxidase-containing soybean wheywith a water solution of a polysaccharide gum from the group consistingof sodium alginate, Irish moss, gum karaya, and agar and recovering fromthe reaction mixture a complex of soybean proteins and saidpolysaccharide gum having lipoxidase activity.

3. A composition having lipoxidase activity comprising a complex oflipoxidase-containing soybean whey proteins and a polysaccharide gum.

4. A composition having lipoxidase activity comprising a complex oflipoxidase-containing soybean whey proteins and a polysaccharide gumfrom the group consisting of sodium alginate, Irish moss, gum karaya,and agar.

1950-51, Interscience Publishers Inc., New York, pages 312, 360, 963. V

3. A COMPOSITION HAVING LIPOXIDASE ACTIVITY COMPRISING A COMPLEX OFLIPOXIDASE-CONTAINING SOYBEAN WHEY PROTEINS AND A POLYSACCHARIDE GUM.